Messages in this thread | | | Subject | Re: PCI PM: Restore standard config registers of all devices early | From | Benjamin Herrenschmidt <> | Date | Tue, 03 Feb 2009 08:00:37 +1100 |
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On Mon, 2009-02-02 at 12:41 -0800, Linus Torvalds wrote: > > On Tue, 3 Feb 2009, Benjamin Herrenschmidt wrote: > > > > I'd rather hook it up inside pci_set_power_state()... > > Umm. But you already _have_ that. Look at platform_pci_set_power_state(). > It gets called before turning the device on (pci_raw_set_power_state(D0)) > and after turning the device off (pci_raw_set_power_state(D1+)) > > Maybe you missed it? It's how ACPI does things.
I may well have, it didn't exist when my stuff was written.
> However, the issue you see is that pci_restore_standard_config() doesn't > call it, because at least with ACPI, the ACPI code simply isn't ready to > be called with interrupts off. So it looks like you may be looking at the > wrong thing, hmm?
Well.. yes and no... I still don't see how it can be sane to whack config space back before the device has been turned back on. I wouldn't be surprised if some devices don't grok well their BARs being written while not in D0.
I suppose I can always add another hook inside pci_restore_blah for my specific case but I can also very easily see that can of worms hitting even more badly in tight embedded environments such as handhelds, who use things like fine clock control a lot more extensively.
In fact, even on x86, I'm not sure it's kosher to restore the config space before you called ACPI...
Ben.
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